Member Since: 22 Jul 2019
Location: seattle, wa
Posts: 43
LR4 5.0 cooling fan always on
Hello friends!
I added a D4 HSE LUX (with lockers and camera kit wooo) to my fleet
Just a few wriggles to sort, and I’m down to the last one:
The cooling fan. It’s always on. Cold start on a 32° f morning? Yep. On.
It sounds like a jet engine is taking lift when my wife drives off. The other D4 I test drove didn’t do this. The clutch does let go at higher RPM so I don’t think it’s stuck/binding. If I give it a good push by hand, it spins about a half turn before stopping. As far as I can tell it’s fine.
I think I read somewhere that it’s a “electro-viscous” clutch, so I’m assuming there might be some electronic trigger engaging it? There is a small loom running to it.
I don’t have the low coolant warning or any odd temps.
Cheers
2010 NAS Disco 4 HSE LUX HD petrol
1994 NAS RRC LWB V8 petrol - SOLD
2006 NAS Disco 3 V8 petrol
2006 NAS RRS HSE petrol - SOLD
2003 NAS Disco 2 SE7 petrol
2003 NAD Disco 2 SE - SOLD
2001 Disco 2 SE - SOLD
2003 Disco 2 SE7 - SOLD
1995 Disco SE - SOLD
1997 Disco SE - SOLD
7th Nov 2021 2:55 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4651
Check for fault codes in the engine PCM, but it is as you suggest a viscous coupling with electronic control (hence the cables!). Under normal operation it should "grab" the fan on start up and release it as soon as the viscous coupling reaches a predetermined state, (fluid dispersal) usually no more than 1-2 minutes of operation.
If the engine temperature raises either by ambient means or through workload, the viscous coupling will again "grab" the fan to initiate additional cooling through the radiator.
So it could be a fault with the viscous coupling, the temp sensor, or the wiring to the fan coupling itself.
The fault codes will point the way. yµ (idµ - eAµ) ψ=mψ
7th Nov 2021 4:43 am
reverendalc
Member Since: 22 Jul 2019
Location: seattle, wa
Posts: 43
Thanks for that. I did scan for codes.
Only two intermittent codes for O2 sensor. Nothing about any of that jazz.
The fan never lets go, ever. The absence of codes leads me to believe that it’s a mechanical issue, but the clutch feels normal to me. I guess I could (safely) try to stop it from spinning while running to see
I feel like then it might be electrical, but the absence of any related codes sends my head spinning back to the mechanical action.
Do you happen to know what to expect if I unplug that harness to the clutch? (-:2010 NAS Disco 4 HSE LUX HD petrol
1994 NAS RRC LWB V8 petrol - SOLD
2006 NAS Disco 3 V8 petrol
2006 NAS RRS HSE petrol - SOLD
2003 NAS Disco 2 SE7 petrol
2003 NAD Disco 2 SE - SOLD
2001 Disco 2 SE - SOLD
2003 Disco 2 SE7 - SOLD
1995 Disco SE - SOLD
1997 Disco SE - SOLD
7th Nov 2021 5:14 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4651
OK that seems a bit odd there's no codes even though there appears to be an obvious fault.
In the old days when there was no electronic fan management, I used to get a pair of reasonably strong elastic bands and tie one end to a fan blade, and the other to a fixed point on the engine. When the engine reached (or rather exceeded) operating temperature, it should easily rip the bands if the viscous clutch was engaging OK.
Your situation if the opposite of that, but in the presence of no fault codes you can only assume the mechanical side of the viscous coupling is at fault.
Assuming you are using a decent diagnostic tool the only option is to renew the coupling. If on the other hand you're using generic diagnostics, I'd get it checked with dedicated LR diagnostics before firing the parts cannon. yµ (idµ - eAµ) ψ=mψ
7th Nov 2021 5:50 am
reverendalc
Member Since: 22 Jul 2019
Location: seattle, wa
Posts: 43
I only put my foxwell on it, but it’s a dedicated JLR tool and works great on my LR3, RRS, etc. I have a nanocom, but BBS wants a LOT of money for the D4 software. Like $300USD, so I’ve been putting that purchase off in favor of cooler stuff like a new viscous clutch.
If the clutch was failed in the locked position, I shouldn’t be able to turn it by hand when off… at least not easily right? Perhaps if I stuff a rolled up magazine in there while it’s running, I shouldn’t be able to stop the rotation if it’s engaged.
Also, do you know what happens if the clutch is unplugged?
Thanks!2010 NAS Disco 4 HSE LUX HD petrol
1994 NAS RRC LWB V8 petrol - SOLD
2006 NAS Disco 3 V8 petrol
2006 NAS RRS HSE petrol - SOLD
2003 NAS Disco 2 SE7 petrol
2003 NAD Disco 2 SE - SOLD
2001 Disco 2 SE - SOLD
2003 Disco 2 SE7 - SOLD
1995 Disco SE - SOLD
1997 Disco SE - SOLD
7th Nov 2021 5:59 am
garrycol
Member Since: 06 Dec 2010
Location: Canberra
Posts: 1115
Do the fans go off if you turn climate control off?
7th Nov 2021 8:44 am
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8091
I see another Disco parked behind, swap the fans over and see what happens It can when others can't,
It will when others won't,
It goes where others don't.
7th Nov 2021 9:41 am
reverendalc
Member Since: 22 Jul 2019
Location: seattle, wa
Posts: 43
Nah, like I said the fan is always engaged, except when it slips off at higher rpm.
That’s a D2 and a D3, neither of which is a suitable candidate for swapping.
Nobody knows what happens when the clutch is unplugged?2010 NAS Disco 4 HSE LUX HD petrol
1994 NAS RRC LWB V8 petrol - SOLD
2006 NAS Disco 3 V8 petrol
2006 NAS RRS HSE petrol - SOLD
2003 NAS Disco 2 SE7 petrol
2003 NAD Disco 2 SE - SOLD
2001 Disco 2 SE - SOLD
2003 Disco 2 SE7 - SOLD
1995 Disco SE - SOLD
1997 Disco SE - SOLD
7th Nov 2021 3:08 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4651
If it's disconnected the fan should in theory go to "idle" but this could cause overheating if you leave it that way. A fault code should be logged if you try it temporarily, but you'd imagine it should "let go" if unplugged and is working correctly?
Just a thought!yµ (idµ - eAµ) ψ=mψ
7th Nov 2021 4:51 pm
reverendalc
Member Since: 22 Jul 2019
Location: seattle, wa
Posts: 43
That was my hope/supposition as well… that without the electrical interface, it would not engage.
I guess it boils down to whether the clutch is normally engaged unless electrically instructed to disengage, or if the clutch is normally disengaged and the electronics cause it to engage on demand.
When it stops outside, I’ll give it a whirl, but without knowing the intended behavior I’ll not know if I’m proving or disproving a theory lol2010 NAS Disco 4 HSE LUX HD petrol
1994 NAS RRC LWB V8 petrol - SOLD
2006 NAS Disco 3 V8 petrol
2006 NAS RRS HSE petrol - SOLD
2003 NAS Disco 2 SE7 petrol
2003 NAD Disco 2 SE - SOLD
2001 Disco 2 SE - SOLD
2003 Disco 2 SE7 - SOLD
1995 Disco SE - SOLD
1997 Disco SE - SOLD
7th Nov 2021 5:01 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4651
Well it's principle operating cycle is based on hydraulic flow as it is a viscous coupling after all.
That said, LR say it should go to idle when the plug is disconnected but this applies to the 4.0l. So I'm making an assumed operating relationship for your engine as being the same!!yµ (idµ - eAµ) ψ=mψ
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outside, I’ll give it a whirl, but without knowing the intended behavior I’ll not know if I’m proving or disproving a theory lol
